[IR] Refactored GET_FIELD, SET_FIELD for inline classes + test

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/Autoboxing.kt

@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.backend.common.atMostOne
 import org.jetbrains.kotlin.backend.common.ir.copyTo
 import org.jetbrains.kotlin.backend.common.lower.*
 import org.jetbrains.kotlin.backend.konan.*
-import org.jetbrains.kotlin.backend.konan.descriptors.target
 import org.jetbrains.kotlin.backend.konan.ir.*
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
@@ -243,26 +242,32 @@ private class InlineClassTransformer(private val context: Context) : IrBuildingT
         return declaration
     }
 
-    private fun IrField.isInlinedClassField(): Boolean {
-        val parentClass = this.parent as? IrClass
-        return parentClass != null && parentClass.isInlined()
-    }
-
     override fun visitGetField(expression: IrGetField): IrExpression {
         super.visitGetField(expression)
 
-        return if (expression.symbol.owner.isInlinedClassField()) {
-            expression.receiver!!
-        } else {
+        val field = expression.symbol.owner
+        val parentClass = field.parentClassOrNull
+        return if (parentClass == null || !parentClass.isInlined())
             expression
+        else {
+            builder.at(expression)
+                    .irCall(symbols.reinterpret, field.type,
+                            listOf(parentClass.defaultType, field.type)
+                    ).apply {
+                        extensionReceiver = expression.receiver!!
+                    }
         }
     }
 
     override fun visitSetField(expression: IrSetField): IrExpression {
         super.visitSetField(expression)
 
-        return if (expression.symbol.owner.isInlinedClassField()) {
+        return if (expression.symbol.owner.parentClassOrNull?.isInlined() == true) {
             // TODO: it is better to get rid of functions setting such fields.
+            // Here we're trying to maintain all IR nodes as is, albeit the transformed IR isn't equivalent to the original.
+            // By far SET_FIELD can only be in the constructor which won't be codegened.
+            // Box functions use createUninitializedInstance instead of constructor calls
+            // and are placed separately so they won't be processed here.
             val startOffset = expression.startOffset
             val endOffset = expression.endOffset
             IrBlockImpl(startOffset, endOffset, irBuiltIns.unitType).apply {

backend.native/tests/build.gradle

@@ -3110,6 +3110,10 @@ task inlineClass_customEquals(type: KonanLocalTest) {
     source = "codegen/inlineClass/customEquals.kt"
 }
 
+task inlineClass_defaultEquals(type: KonanLocalTest) {
+    source = "codegen/inlineClass/defaultEquals.kt"
+}
+
 task deserialized_inline0(type: KonanLocalTest) {
     source = "serialization/deserialized_inline0.kt"
 }

backend.native/tests/codegen/inlineClass/defaultEquals.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+package codegen.inlineClass.defaultEquals
+
+import kotlin.test.*
+
+inline class A(val x: Int)
+inline class B(val a: A)
+inline class C(val s: String)
+inline class D(val c: C)
+
+@Test fun runTest() {
+    val a = A(42)
+    val b = B(a)
+    val c = C("zzz")
+    val d = D(c)
+    assertTrue(a.equals(a))
+    assertTrue(b.equals(b))
+    assertTrue(c.equals(c))
+    assertTrue(d.equals(d))
+}